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We can C++ project and we need to (de) serialize objects from and into json.
In C# we are using JSON.NET. We simple call:
string json = JsonConvert.SerializeObject(product);
var myNewObject = JsonConvert.DeserializeObject<MyClass>(json);
Very simple and useful.
Does anybody know about free C++ library, which can be used in the same simple way like in C#?
We are using JsonCpp, but it does not support it.
Thanks very much
Regards
C++ does not support reflection so you necessarily have to write your own serialize and deserialize functions for each object.
I'm using https://github.com/nlohmann/json in a C++ websocket server talking to a html/javascript client. The websocket framework is https://github.com/zaphoyd/websocketpp. So sending the json structure 'matches' from the server goes like
msg->set_payload(matches.dump());
m_server.send(hdl, msg);
And like wise from the client
var m = "la_liga";
var msg = {
"type": "request",
"data": m
}
msg = JSON.stringify(msg);
ws.send(msg);
When I receive json on the server I parse it and then a try-catch
void on_message(connection_hdl hdl, server::message_ptr msg) {
connection_ptr con = m_server.get_con_from_hdl(hdl);
nlohmann::json jdata;
std::string payload = msg->get_payload();
try {
jdata.clear();
jdata = nlohmann::json::parse(payload);
if (jdata["type"] == "update") {
<do something with this json structure>
}
} catch (const std::exception& e) {
msg->set_payload("Unable to parse json");
m_server.send(hdl, msg);
std::cerr << "Unable to parse json: " << e.what() << std::endl;
}
}
And likewise on the client
ws.onmessage = function (e) {
var receivedMsg = JSON.parse(e.data);
if (receivedMsg.type == "table") {
<sort and display updated table standing>
}
}
Websocketpp requires boost libraries.
I wrote this serializer/deserializer for c++ since I couldn't find any non boost serializer that fit my needs:
Pakal Persist
It supports both json and xml and polymorphics objets as well.
Related
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Have this code where i am trying to run a loop for few times to make sure i do get my result, but for some reason, i am still getting an error displayed on sreen and it is not even doing the cflog so i can know what is going on, any help will be appreciated
var aData = [];
for (i = 1; i <= 10; i++) {
try {
var a = {};
var as = calltoapitoogetdata;
a['count'] = as;
ArrayAppend(aData, mData);
var retJSON = serializeJSON(aData);
writedump(retJSON);
//return serializeJSON(aData);
break;
} catch (any e) {
i = i + 1;
cflog(text = "Call failed #i#", application = true, file = "loogevent");
writedump(i);
}
}
Thanks
If your code is still erroring it is most likely coming from the cflog call being made in your cfcatch. If you are running a version of Adobe ColdFusion the script version would be :
WriteLog(type="Error", file="myapp.log", text="[#ex.type#] #ex.message#");
https://helpx.adobe.com/coldfusion/cfml-reference/coldfusion-functions/functions-t-z/writelog.html
Lucee has made many of the CFScript functions equivalent of their tag names but with Adobe CF there are a number of functions that do not comply with this. <cfdump> -> writeDump for example.
Too long for a comment.
I think troubleshooting is easier if all available information is right in front of you on the screen. So, I would troubleshoot like this. Your code is below with my additions in uppercase:
var aData = [];
for (i = 1; i <= 10; i++) {
try {
WRITEOUTPUT('TRY NUMBER #I# <BR>);
var a = {};
var as = calltoapitoogetdata;
WRITEDUMP(AS);
a['count'] = as;
ArrayAppend(aData, mData);
var retJSON = serializeJSON(aData);
writedump(retJSON);
//return serializeJSON(aData);
break;
} catch (any e) {
i = i + 1; // THIS LINE IS NOT NECESSARY
WRITEOUTPUT('CATCH NUMBER #I# <BR>);
cflog(text = "Call failed #i#", application = true, file = "loogevent"); //THIS LINE GETS REPLACED BY
WRITEDUMP(E);
writedump(i); // THIS LINE GOES AWAY
}
}
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Is it possible to use an operator || in json like this :
{
"ven":{
"source":"logicCtrl" ,
"msg":"radio_volume" || "radio-mute", || "radio3",
"type":"int"
}
}
i can after get data by parsing data in C++ side like this :
QFile jsonFile("VenParser.json");
if (!jsonFile.open(QIODevice::ReadOnly | QIODevice::Text))
{
qDebug() << "problème d'overture du fichier, exit";
}
QByteArray jsonData = jsonFile.readAll();
QJsonParseError *err = new QJsonParseError();
QJsonDocument doc = QJsonDocument::fromJson(jsonData, err);
if (err->error != 0)
qDebug() << err->errorString();
Venparser myparser;
if (doc.isNull())
{
qDebug() << "Document invalide";
}
else if (doc.isObject())
{
//recuperer l'object json
QJsonObject jObject = doc.object();
//convertir l'object json to variantmap
QVariantMap mainMap = jObject.toVariantMap();
// variant map
QVariantMap Map = mainMap["ven"].toMap();
myparser.source = Map["source"].toString();
myparser.msg = Map["msg"].toString();
myparser.type = Map["type"].toString();
header.H file : i define my struct
struct Venparser {
QString source;
QString msg;
QString type;
My problem is that i don't want a list in my "msg" but something like this :
when i call myparser.msg , then it will check just the value i need in msg and return it.
"msg":"radio_volume" || "radio-mute", || "radio3",
Thanks,
Your example with the || token is not a valid JSON. You can read more about its format here. However, if I understand you correctly, you can easily use JSON arrays for your task.
JSON:
{
"ven": {
"source": "logicCtrl",
"msg": ["radio_volume", "radio-mute", "radio3"],
"type": "int"
}
}
C++:
You can access the msg array using the toStringList() method. Also, you can use QVariantList and toList() respectively if you fill your array with data different from strings.
QStringList messages = Map["msg"].toStringList();
Now the messages variable contains "radio_volume", "radio-mute" and "radio3" values so you can extract the required string any way you need using your code.
If you still need to parse your exact example (which is technically not a valid JSON as I said before), you will have to go with writing your own parser, which is a bit wide topic for the answer.
I have built a dll which includes a class implementing the mongoDB replicaset operations. Here is a summary of the class.
#include "mongo/client/dbclient.h"
mongoimp::mongoimp() {
mongo::client::initialize();
}
mongoimp::~mongoimp() {
mongo::client::shutdown();
}
int mongoimp::queryTRecords() {
string errmsg;
vector<mongo::HostAndPort> hosts = { mongo::HostAndPort("xx-a0.yyyy.com:xxxxx"), mongo::HostAndPort("xx-a1.yyyy.com:xxxxx") };
static mongo::DBClientReplicaSet con("xx", hosts, 0);
con.connect();
con.auth("dbname", "username", "password", errmsg);
auto_ptr<DBClientCursor> cursor = con.query("dbname.t", BSONObj());
BSONObj response;
con.logout("xx", response);
if (cursor->more()) {
BSONObj recordnm = cursor->nextSafe();
return(recordnm.getIntField("lastid"));
} else return(-1);
}
The above code is working. But here are my questions:
1) With the above setting, I can do normal mongoDB operations with the dll but since my application needs to constantly update mongoDB data (close to real-time, up to hundreds a second), I am getting error (No valid replicaset instance servers found) when updating data.
2) Only the server needs to talk to the mongoDB database. So basically I just need one connection to the database. So I want to declare the mongo::DBClientReplicaSet con as a static global variable and connect to it in the class construct function. But it seemed I cannot do it. My application cannot run at all. With that, I constantly get the following error.
Assertion failed: px != 0, file C:\Boost\include\boost-1_62\boost/smart_ptr/scoped_ptr.hpp, line 105
Does anybody know how to solve the problem?
Below is the code I tried:
static mongo::DBClientReplicaSet con("xx", { mongo::HostAndPort("xx-a0.yyyy.com:xxxxx"), mongo::HostAndPort("xx-a1.yyyy.com:xxxxx") }, 0);
mongoimp::mongoimp() {
mongo::client::initialize();
string errmsg;
con.connect();
con.auth("dbname", "username", "password", errmsg);
}
mongoimp::~mongoimp() {
BSONObj response;
con.logout("xx", response);
mongo::client::shutdown();
}
int mongoimp::queryTRecords() {
auto_ptr<DBClientCursor> cursor = con.query("dbname.t", BSONObj());
if (cursor->more()) {
BSONObj recordnm = cursor->nextSafe();
return(recordnm.getIntField("lastid"));
} else return(-1);
}
3) Last question, I noticed there is mongo/client/dbclient_rs.h" file for replicaset. But it seemed I cannot use it. With that, I am getting error for initialize() and auto_ptr cursor. How can I use the file and take full advantage of replicaset features? How can I initialize the relica set if I can use "dbclient_rs.h"? How do I do query and fetch data in that case?
Thanks a lot in advance!
For question No. 2, I remembered the reason for the error:
You need to call mongo::client::initialize before you construct any driver objects, or BSON for that matter.
But how to make that global definition possible, I still need a solution.
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I'm just wondering is there a way to give or rename a container like chest that is already on ground?
I mean not using NMS. But the spigot API to edit the names?
There is no API for it but it is possible with NMS. I made this method some time ago, it allows you to name any tile entity.
You give it a normal bukkit block and name that will be applied to the block. Name can have § coloring char.
With this code you can make version using reflections if you want to avoid NMS and CB imports.
import net.minecraft.server.v1_8_R1.INamableTileEntity;
import net.minecraft.server.v1_8_R1.TileEntity;
import net.minecraft.server.v1_8_R1.TileEntityBrewingStand;
import net.minecraft.server.v1_8_R1.TileEntityChest;
import net.minecraft.server.v1_8_R1.TileEntityCommand;
import net.minecraft.server.v1_8_R1.TileEntityDispenser;
import net.minecraft.server.v1_8_R1.TileEntityEnchantTable;
import net.minecraft.server.v1_8_R1.TileEntityFurnace;
import net.minecraft.server.v1_8_R1.TileEntityHopper;
import org.bukkit.block.Block;
import org.bukkit.craftbukkit.v1_8_R1.CraftWorld;
public static void setName(String name, Block block) {
final CraftWorld world = (CraftWorld) block.getWorld();
final TileEntity nmsTileEntity = world.getTileEntityAt(block.getX(), block.getY(), block.getZ());
if (nmsTileEntity instanceof INamableTileEntity) {
if (nmsTileEntity instanceof TileEntityChest) {
((TileEntityChest) nmsTileEntity).a(name);
} else if (nmsTileEntity instanceof TileEntityFurnace) {
((TileEntityFurnace) nmsTileEntity).a(name);
} else if (nmsTileEntity instanceof TileEntityDispenser) {
((TileEntityDispenser) nmsTileEntity).a(name);
} else if (nmsTileEntity instanceof TileEntityHopper) {
((TileEntityHopper) nmsTileEntity).a(name);
} else if (nmsTileEntity instanceof TileEntityBrewingStand) {
((TileEntityBrewingStand) nmsTileEntity).a(name);
} else if (nmsTileEntity instanceof TileEntityEnchantTable) {
((TileEntityEnchantTable) nmsTileEntity).a(name);
} else if (nmsTileEntity instanceof TileEntityCommand) {
((TileEntityCommand) nmsTileEntity).getCommandBlock().setName(name);
}
nmsTileEntity.update();
}
}
I use wxFTP to make simple client and I'm stucked on how to Upload recursively my folder or do download (which would should be same as delete) from FTP server. I know how to upload single file, make FTP folder and delete file. I will appreciate an article (not necessarily in C/C++) that teaches the concept or if someone can help me here.
Code example will be appreciated but take that as secondary.
Sorry if it already asked and answered, I searched and didn't get anything that answered my question.
I translated the code in answer to this question to C++ and that was it.
Since So won't accept the answer and adds it to comments I have added Java code that I translated to C++. My current code is too long (in that it involves few functions and so not fit for SO I guess!
public void saveFilesToServer(String remoteDest, File localSrc) throws IOException {
FTPClient ftp = new FTPClient();
ftp.connect("ftp.foobar.com");
if (!FTPReply.isPositiveCompletion(ftp.getReplyCode())) {
ftp.disconnect();
log.fatal("FTP not disconnected");
}
ftp.login("foo", "qwerty");
log.info("Connected to server .");
log.info(ftp.getReplyString());
ftp.changeWorkingDirectory(remoteDest);
ftp.setFileType(FTPClient.BINARY_FILE_TYPE);
try {
upload(localSrc, ftp);
}
finally {
ftp.disconnect();
log.info("FTP disconnected");
}
}
public void upload(File src, FTPClient ftp) throws IOException {
if (src.isDirectory()) {
ftp.makeDirectory(src.getName());
ftp.changeWorkingDirectory(src.getName());
for (File file : src.listFiles()) {
upload(file, ftp);
}
ftp.changeToParentDirectory();
}
else {
InputStream srcStream = null;
try {
srcStream = src.toURI().toURL().openStream();
ftp.storeFile(src.getName(), srcStream);
}
finally {
IOUtils.closeQuietly(srcStream);
}
}
}